In Japan, Kuro is not used for meaning the colour black. Kuro nearly almost all the time is given for the ninth son. It can also be made up of other Kanji combinations, but never just black (黒). In anime, yes the fictional characters have the name Kuro meaning black (黒), but that doesn't mean real life Japan uses it. (http://jisho.org/search/%E9%BB%92%23name).
Kuro Yatogami is a sword wielding samurai-like character in the anime K. He tries several times to kill the main character but I can't help but love the name and the character associated with it.